论文部分内容阅读
利用自制的三轴渗透装置,在低渗透煤层中注入CO2,测定不同孔隙压力下非超临界和超临界CO2的流速,通过显微CT成像观察超临界CO2作用前后煤层微观截面孔隙裂隙的变化.结果表明:超临界CO2作用后,流速较非超临界CO2作用时明显提高;随着孔隙压力的增加,CO2的流速呈指数递增的关系;煤层微观截面CT图显示,超临界CO2作用后,孔隙、裂隙较非超临界CO2作用时明显发育、尺寸增大、密度增加、连通性提高,说明由于超临界CO2的作用进一步促进了煤层微观孔隙、裂隙的充分发育,增加了渗流通道,有效提高了煤层的渗透性.
By using self-made three-axis infiltration device, CO2 was injected into the low permeability coal seam to measure the flow rate of non-supercritical and supercritical CO2 under different pore pressures. The changes of pore fractures in the micro-section of coal seam before and after supercritical CO2 were observed by micro-CT imaging. The results show that the flow rate of supercritical CO2 increases obviously as compared with that of non-supercritical CO2. With the increase of pore pressure, the flow rate of CO2 increases exponentially. The CT images of the micro-section of coal seam show that after supercritical CO2, , The fractures developed obviously when compared with the non-supercritical CO2, the size increased, the density increased and the connectivity increased, which indicated that the superficial CO2 could further promote the microscopic pores and fractures and increase the seepage channel Seam permeability.